Sheet containing developer for pressure-sensitive recording

ABSTRACT

A pressure sensitive recording developer sheet comprising a phenolic resin developer coating on a support, the improvement which comprises said phenolic resin developer being a resin which is obtained by modifying with an alkylphenol compound represented by the general formula   WHEREIN R1R2 and R3 which may be the same or different each represents a hydrogen atom or an alkyl group with the proviso that they simultaneously should not be hydrogen atoms, in the condensation of p-phenyl phenol and aldehyde. The coating may also contain microcapsules containing a substantially colorless coupler.

United States Patent [191 Hayashi Dec. 31, 1974 SHEET CONTAININGDEVELOPER FOR PRESSURE-SENSITIVE RECORDING [75] Inventor: Takao Hayashi,Fujimiya, Japan [73] Assignee: Fuji Photo Film Co., Ltd.,

Kanagawa, Japan [22] Filed: Mar. 8, 1972 [21] Appl. No.: 232,938

[30] Foreign Application Priority Data Primary Examiner-William D.Martin- Assistant Examiner-Bernard D. Pianalto Attorney, Agent, orFirm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A pressuresensitive recording developer sheet comprising a phenolic resindeveloper coating on a support, the improvement which comprises saidphenolic resin developer being a resin which is obtained by modifyingwith an alkylphenol compound represented by the general formula whereinR R and R;, which may be the same or different each represents ahydrogen atom or an alkyl group with the proviso that theysimultaneously should not be hydrogen atoms, in the condensation ofpphenyl phenol and aldehyde. The coating may also contain microcapsulescontaining a substantially colorless coupler.

14 Claims, N0 Drawings SHEET CONTAINING DEVELOPER FOR PRESSURE-SENSITIVERECORDING BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to a sheet containing a developer for pressuresensitive recording. More particularly, it relates to an improvement inthe phenol resin which is used as a developer for pressure sensitiverecording.

2. Description of the Prior Art A pressure sensitive recording sheetutilizes the reaction of an almost colorless organic compound(hereinafter described as the coupler.) and a developing substance whichcan react with the coupler to form a colored product (hereinafterdescribed as the developer). More particularly, it comprises a sheetcoated with mirocapsules containing a solution of a coupler in anorganicsolvent (a coupler sheet) and a sheet coated with a developertogether with a binder (a developer sheet) and, occasionally a sheet inwhich a developer is coated on one surface of a support and themicrocapsules are coated on the opposite surface (hereinafter describedas a pressure sensitive copying sheet). In another embodiment, there isa sheet in which the microcapsules and developer are coated on the samesurface of a support.

As couplers, there have been used Malachite Green Lactone, Benzoyl LeucoMethylene Blue, Crystal Violet Lactone, Rhodamine B Lactam,3-dialkylamino-7- dialkylaminofluorans and3-methyl-2,2'-spirobi(benzo(f)cumene), and the like.

As substances which react with the coupler to form colored products,there have been used generally clays such as acid clay, active earth,attapulgite, zeolite and bentonite; organic acid compounds such assuccinic acid, tannic acid and gallic acid. Recently, it has been newlyproposed to use a phenol resin as developer. That is, British Pat. No.1,065,587 describes the combined use of an oil soluble polymer such as aphenol resin and an acid mineral such as attapulgite as a developer andJapanese Pat. No. 511,757 describes also a polymer such as a phenolresin as a developer. While the phenol resin as a developer hasexcellent properties in that a water stable colored image on reactingwith a coupler such as, for example, Crystal Violet Lactone, is formedit has an insufficient'developing capacity and tends to change readilyto yellow in the daylight or on storage in a room disadvantageously.

An object of this invention is an improved pressure sensitive copyingsheet.

Another object of this invention is to use an improved phenol resin as adeveloper for pressure sensitive recording.

SUMMARY OF THE INVENTION wherein R R and R which may be the same ordifferent, each represents a hydrogen atom or an alkyl group with theproviso that they are not simultaneously hydrogen atoms, and analdehyde.

DETAILED DESCRIPTION OF THE INVENTION the presence ofa catalyst at aboutto about 200C for several hours.

In the manufacture of the phenol resin of this invention, from about 0.2to about 2 mols of the phenol represented by the above general formulaare suitable for each mol of p-phenyl phenol. While the amount ofaldehyde used has little effect on the resin obtained, from about 0.5 toabout 2 mols of aldehyde to each mol of phenol i.e., the sum of thep-phenyl phenol and the alkyl phenol, is preferred.

While formaldehyde, acetaldehyde, propionaldehyde and other aldehydesmay be used as the aldehyde employed, the reaction takes place withgreater difficulty as the number of carbon atoms of the aldehydeincreases. Generally, aliphatic monoaldehydes having from I to about 3carbon atoms are preferred. Formaldehyde is especially preferred.

In general, an acid may be used as catalyst; for example, hydrochloricacid, sulfuric acid, oxalic anhydride and the like are suitable.

The amount of the catalyst used can be varied and in general from about5 to about 20cc of 37% hydrochloric acid and from about 1 to about 10gfor oxalic anhydride can be used. In the use of a solid catalyst, it maybe dissolved in a solvent for use.

The resulting modified phenol resin is separated from the liquid phase,dissolved in an organic solvent such as acetone, methyl ethyl ketone,butyl acetate, benzene, toluene, xylene and the like or dispersed in anaqueous binder solution and coated on a paper surface. In anotherembodiment, the modified phenol resin can be dissolved in an organicsolvent, dispersed in aqueous binder solution and coated on a papersurface.

As binders, styrene-butadiene latex, maleic anhydride-styrene copolymer,polyvinyl alcohol, starch, casein, ethyl cellulose, styrenebutadienecopolymer, polyvinyl acetate, polyvinylidene chloride, vinylchloridevinylidene chloride copolymer and the like are suitable.

The amount of binder generally used ranges from about 5 to about 30parts by weight per 100 parts by weight of the modified phenol resin.

The developer layer of this invention may contain clay minerals having adeveloping capacity, e.g., Japanese acid clay or active clay or aninorganic pigment having an adsorption capability or a mixture thereof.

In comparision with developer sheets using previous phenol resins, thedeveloper sheet using the phenol resin obtained in this invention has astrong developing invention capacity with respect to the coupler andexcellent properties in that it changes to yellow in the daylight or onstorage in a room with difficulty.

The phenol resins'described in the above referred British Pat. No.1,065,587 and Japanese Pat. No. 511,757 were obtained by thecondensation of a single phenol compound with an aldehyde. As discussedabove, however, the developer sheet for pressure sensitive copying usingthis phenol resin of a single phenol compound does not have sufficientdeveloping capacity and tends to be discolored into yellow in thedaylight or on storage in a room. i v I The phenolresin according tothis invention is obtained by the condensation of at least two phenolcom. pounds with an aldehyde. The developer sheet for pressure sensitivecopying using the phenol resin obtained by the method as described aboveemploying at least two phenol compounds has'excellent properties in thatit has a strong developing capacity and changes with difficulty intoyellow in the daylight or on storage in a room. 4

When the relation between the chemical composition of the phenol resinof this invention and developing capacity and yellow discolorationresistance of the developer sheet for pressure sensitive copying basedon the fact as mentioned above, it is obvious that a useful effect isobtained by the use of the phenol resin prepared sheet:

A microcapsul econtaining coupler wasprepare'd, for

example, according to disclosure in US. Pat. No.

2,800,457 andan example thereof is described asfollows:

10 parts of pigle'ather acid-treatedgelatin and 10 parts-of gum a'rabicare dissolved in 400 parts of water, 02 part of Turkey red oil is addedas an emulsifier and 40 parts of oil coupler are emulsified therein. Thecoupler oil contains 2% of Crystal Violet Lactone dissolved in an oilconsisting of 4 parts of diphenyl chloride and 1 part of kerosene.

When the size of the oil droplets is on an average of 5 u, the emulsification is ceased. Waterat 40C is added thereto to make 900 partstotal and the. stirring is continued, during which time the liquidtemperature should fall below 40C. 10% acetic acid is then'added toadjust the pH-value of liquid to 4.0 4.."2 resulting incoacervatiomAfter stirring for a 20 minute period, it

is cooled by ice water to gel the coacervate film depo's- 30C, coated inan amount of 6g(solid)/m on a paper of 40g/m and dried.

' 4 Other coupler containing sheets using microcapsules containingMalachite Green Lactone, Benzoyl Leuco Methylene Blue, Rhodamine BLactum, 3-

dialkylamino-7-dialkylamino-fluorans and 3-methyl- 2,2-spiro (benzo (f)cumene) or mixtures thereof as the couplers were prepared in the samemanner as described above for the Crystal Violet Lactone.

EXAMPLE 1 g of p-phenyl phenol, 75g of p-t-butyl phenol. g of aqueous37% formaldehyde, 10 ml'of conc. hydrochloric acid (37%) and-50ml ofwater were placed in a kettle to prepare the-resin and heated at C for10 hrs. The resulting resin was cooledand then ground. 10g of theresulting resin were dissolved in 40 ml of acetone, coated in an amountof 2g/m and dried.

. CONTROL 1 g of p-phenyl phenol, 100g of aqueous 37% formaldehyde, 10ml of cone hydrochloric acid (37% and 50cc of water were placed inakettle for to prepare a resin and heated at 140C for 10 hrs. Theresulting resin was cooled and then ground. 10g of the resulting resinwere dissolved in 40 ml of acetone, coated in an amountof Zg/m on apaper of 40 g/m and dried.

EXAMPLE 2 85g of p-phenyl phenol, 55g of p-nonyl phenol, 50g of aqueous37% formaldehyde, l0g'of oxalic anhydride and 5.0 mlof water were placedin a kettle to prepare the resin and heated at C for 5 hrs. Theresulting resin was cooled and then ground. 10g of the resultingresin'were dissolved in;4 0 ml of benzene, coated inan amount of 2 g/mon apaper of 40 g/m and dried.

I CONTROL 2 -127.5g of pphenyl phenol,"50g of aqueous 37 7gjformaldehyde, 10g oxalic anhydride and 50 ml of water were placed in akettleto prepare the resin and heated at 180C for 5 hrs. Theresultingresin was cooled and then ground. IOgjof the resulting resin weredissolved .in 40ml of benzene; coated in an amount of 2 gm: on

and dried.

EXAMPLE 3 85g of p-phenyl phenol; 91 .5g' of3,4 -xy lenol, 50g ofaqueous 37%.formaldehyde, 10 ml of cone. hydrochloa paper of 40 g/m' ricacid (37%), lgof oxalic anhydride and 50 ml of water were placed in akettle to prepare the resin and heated at 160C for 8 hrs. The resultingresin was cooled and then ground. 10g of the resulting resin weredissolved in 40 ml of methyl ethyl ketone, coated in an amount of 'g/m?on a paper of 40 g/m and dried.

CONTROL 3 212.5g of p-phenyl phenol. 50g of-aqueous 37%formaldehyde,'l0,m l of cone. hydrochloric acid (37%). 1g

of oxalic anhydride and 50 ml of water were placed in a kettle toprepare the resin and heated at 160C for 8 hrs. 10g of the resultingresin were dissolved in 40 ml of methyl ethyl ketone, coated in anamount of 2'g/m on a paper of 40 g/m and dried. in order toicompare thesamples prepared as described above,the following trols l, 2 and 3 anddeveloped by applying a load pressure of 600 kg/cm After standing for 1hour in the dark, the spectral absorption curve in the wave length rangeof 700 400 mu was measured and the develop ing capacity of eachdeveloper sheets was examined using the density (D,) at the maximumadsorption (610 mu).

2. After exposing each developer sheet of Examples l, 2 and 3 andControls 1,2 and 3 to the sun for 5 hrs, the whiteness of each sheet wasdetermined using a Hunter Brightness Meter and the yellowing tendency ofdeveloper sheet was measured based on the whiteness value.

The results of (1) and (2) are shown in Table I.

Table l whiteness after Sun Exposure for 5 hrs.

Developing Capacity (D,) for Crystal Violet Lactone Example l 0.934

57.4 Control I 0.713 41.8

Example 2 0.877 52.5 Control 2 0.640 373 Example 3 0.878 55.7 Control 30.795 40.6

The same effect was obtained for the other couplers described hereinbefore.

EXAMPLE 4 EXAMPLE 5 The resins obtained as in Examples 2 and 3 arecoated in the same manner as described in Example 4 to obtain asingle-sheet type pressure-sensitive recording paper. While the aboveinvention has been described in detail and with reference to certainembodi ments thereof, it will be recognized that modifications andvariations can be made therein without departing from the spirit andscope thereof.

What is claimed is:

1. In a pressure sensitive recording developer sheet comprising aphenolic resin developer coated on a support, the improvement whichcomprises said phenolic resin developer being the condensation productof pphenyl phenol and at least one alkyl phenol represented by thegeneral formula R2 OH wherein R R and R which may be the same ordifferent, each represents a hydrogen atom or an alkyl group, said alkylgroup containing from 1 to 12 carbon atoms, with the proviso that R Rand R are not simultaneously a hydrogen atom, with an aldehyde. whereinsaid alkyl phenol is present in said condensation product at a level offrom about 0.2 to about 2 moles of said alkyl phenol per mole ofp-phenyl phenol and said aldehyde is present at a level offrom about 0.5to about 2.0 moles of aldehyde per total moles of phenol.

2. The sheet of claim 1 wherein said alkyl phenol is selected from thegroup consisting of p-cresol, p-ethyl phenol, p-t-butyl phenol,p-t-pentyl phenol, p-nonyl phenol, p-dodecyl phenol, p-octyl phenol,3,4-xylenol, and thymol.

3. The sheet of claim 1, wherein said aldehyde is selected from thegroup consisting offormaldehyde, acetaldehyde and propionaldehyde.

4. The sheet of claim 3, wherein said aldehyde is formaldehyde.

5. The sheet of claim I, wherein said phenolic resin developer isincorporatedinto a binder coated on said support.

6. The sheet of claim 5, wherein said binder is selected from the groupconsisting of styrene-butadiene latex, maleic anhydride-styrenecopolymer. polyvinyl alcohol, starch, casein, polyvinylidene chlorideand vinyl chloride-vinylidene chloride copolymer.

7. The sheet of claim 5 wherein said binder is present at a level offrom about 5 to about 30 parts by weight for each parts by weight ofsaid phenolic resin.

8. In a pressure sensitive recording sheet comprising a support havingcoated thereon microcapsules containing a substantially colorlesscoupler and a phenolic resin developer, said coupler being one whichforms a color upon contact with said phenolic resin developer, theimprovement which comprises said phenolic resin developer being thecondensation product of p-phenyl phenol and at least one alkyl phenolrepresented by the general formula where R,, R and R which may be thesame or different, each represents a hydrogen atom or an alkyl grouphaving 1 to [2 carbon atoms, with the proviso that R,, R and R are notsimultaneously a hydrogen atom, with an aldehyde, wherein said alkylphenol is present in said condensation product at a level of from about0.2 to about 2 moles of said alkyl phenol per mole of p-phenyl phenoland said aldehyde is present at a level of from about 0.5 to about 2.0moles of aldehyde per total moles of phenol.

9. The sheet of claim 8 wherein said alkyl phenol is selected from thegroup consisting of p-cresol, p-ethyl phenol, p-t-butyl phenol,p-t-pentyl phenol. p-nonyl phenol, p-dodecyl phenol, p-octyl phenol,3,4-xylenol, and thymol.

10. The sheet of claim 8, wherein said aldehyde is selected from thegroup consisting of formaldehyde, acetaldehyde and propionaldehyde.

11. The sheet of claim 10, wherein said aldehyde is formaldehyde.

12. The sheet of claim 8, wherein said phenolic resin developer isincorporated into a binder coated on said support.

13. The sheet of claim 12, wherein said binder is selected from groupconsisting of styrene-butadiene latex, maleic anhydride-styrenecopolymer, polyvinyl alcohol, starch, casein, polyvinylidene chlorideand vinyl chloride-vinylidene chloride copolymer.

14. The sheet of claim 12 wherein said binder is present at a level offrom about 5 to about 30 parts by weight for each 100 parts by weight ofsaid phenolic

1. IN A PRESSURE SENSITIVE RECORDING DEVELOPER SHEET COMPRISING APHENOLIC RESIN DEVELOPER COATED ON A SUPPORT, THE IMPROVEMENT WHICHCOMPRISES SAID PHENOLIC RESIN DEVELOPER BEING THE CONDENSATION PRODUCTOF P-PHENYL PHENOL AND AT LEAST ONE ALKYL PHENOL REPRESENTED BY THEGENERAL FORMULA
 2. The sheet of claim 1 wherein said alkyl phenol isselected from the group consisting of p-cresol, p-ethyl phenol,p-t-butyl phenol, p-t-pentyl phenol, p-nonyl phenol, p-dodecyl phenol,p-octyl phenol, 3,4-xylenol, and thymol.
 3. The sheet of claim 1,wherein said aldehyde is selected from the group consisting offormaldehyde, acetaldehyde and propionaldehyde.
 4. The sheet of claim 3,wherein said aldehyde is formaldehyde.
 5. The sheet of claim 1, whereinsaid phenolic resin developer is incorporated into a binder coated onsaid support.
 6. The sheet of claim 5, wherein said binder is selectedfrom the group consisting of styrene-butadiene latex, maleicanhydride-styrene copolymer, polyvinyl alcohol, starch, casein,polyvinylidene chloride and vinyl chloride-vinylidene chloridecopolymer.
 7. The sheet of claim 5 wherein said binder is present at alevel of from about 5 to about 30 parts by weight for each 100 parts byweight of said phenolic resin.
 8. In a pressure sensitive recordingsheet comprising a support having coated thereon microcapsulescontaining a substantially colorless coupler and a phenolic resindeveloper, said coupler being one which forms a color upon contact withsaid phenolic resin developer, the improvement which comprises saidphenolic resin developer being the condensation product of p-phenylphenol and at least one alkyl phenol represented by the general formula9. The sheet of claim 8 wherein said alkyl phenol is selected from thegroup consisting of p-cresol, p-ethyl phenol, p-t-butyl phenol,p-t-pentyl phenol, p-nonyl phenol, p-dodecyl phenol, p-octyl phenol,3,4-xylenol, and thymol.
 10. The sheet of claim 8, whereiN said aldehydeis selected from the group consisting of formaldehyde, acetaldehyde andpropionaldehyde.
 11. THE SHEET OF CLAIM 10, WHEREIN SAID ALDEHYDE ISFORMALDEHYDE.
 12. The sheet of claim 8, wherein said phenolic resindeveloper is incorporated into a binder coated on said support.
 13. Thesheet of claim 12, wherein said binder is selected from group consistingof styrene-butadiene latex, maleic anhydride-styrene copolymer,polyvinyl alcohol, starch, casein, polyvinylidene chloride and vinylchloride-vinylidene chloride copolymer.
 14. The sheet of claim 12wherein said binder is present at a level of from about 5 to about 30parts by weight for each 100 parts by weight of said phenolic resin.